The National List of Allowed and Prohibited Substances identifies substances that may and may not be used in organic crop and livestock production. It also lists the substances that may be used in or on processed organic products. In general, synthetic substances are prohibited unless specifically allowed and non-synthetic substances are allowed unless specifically prohibited. For example, a vaccine used to prevent pinkeye in livestock is an allowed synthetic substance and arsenic is an example of a prohibited natural substance. Some substances on the National List may only be used in specific situations, e.g. only for certain crops or up to a maximum amount. View National List.

Adding, Removing, or Changing a Listed Substance. Any individual or organization may submit a petition to amend the National List. The National Organic Standards Board, a Federal Advisory Committee, reviews all petitions and makes formal recommendations to USDA. These recommendations serve as the basis for rulemaking actions. Learn more.

Substance Review. The National Organic Standards Board must review every substance on the National List every five years to confirm that it continues to meet all required criteria. For this review, called the “sunset process,” the NOSB reviews the substance, public comments, and any new information concerning the substance. This could include, for example, reviewing any new information about the substance’s impact to human health or the environment, and any new proven, natural alternatives. As a result of this review, if the NOSB confirms that the substance no longer meets the OFPA criteria, the NOSB can make recommendations to remove the substance from the National List. If USDA agrees with the NOSB’s recommendation to remove, then it may remove the substance from the National List. Changing the National List requires USDA to complete rulemaking, a process which includes another public comment opportunity. View National List Sunset dates (PDF) | View National List criteria.

Petitioned Substances Database. Please use the drop-down box below to view an alphabetical list of National List materials and those petitioned for inclusion. Please note that substances on this site may not be used in organic production or handling unless the substance has been added to the National List through a final rule.